Process for producing hollow cast blocks



intended to keep the head liquid, more or less about 2000 millimetres and a length of about 6 1o Patented July 30, 1940 i I I PROCESS FOR PRODUCING HOLLOW CAST BLOCKS Fritz Halbrock and Wilhelm Baumgardt, Mulheim-on-the-Ruhr, Germany, assignors to Deutsche Rbhrenwerke Aktiengesellschai't, Dusseldorf, Germany, a body corporate No Drawing. Application February 25, 1939, Serial N0. 258,472. In Germany April 28, 1938 .2 Claims. (01. 22-200) It is known to produce hollow cast blocks by that is until the crust has attained the desired introducing the liquid metal into a mold,- and not thickness, and at the same time the hollow cast allowing it to solidify completely but, aiter a crust block has cylindrical shape, which is of great imof the desired thickness has solidified on the po tan e for the su s qu nt t a m nt- T s s 5 mold walls, upsetting the mold and thus removing p s par i u r y w it is desired t Produce I the metal which is still liquid. The difllcuity-oi'ten l rge hollow cast blocks whose wall thickness arises that the head of the ingot solidifies too should amount to as much as V theinternal diquickly and in an irregular shape. 'Even if the ameter of the mold. The molds for still larger known covering substances are used which are blocks have, for example, an internal diameter oi.

parabolically shaped boundary layers form, which metres. The hollow blocks themselves have a make the subsequent treatment of the hollow wallthickness of about 400 to 500 millimetres. blocks much more diificult. Furthermore, the pro- We claim: duction oi predetermined wall thicknesses was 1. A process for producing heavy hollow cast more or less dependent upon chance especially in steel blocks of substantially cylindrical internal u the production of thick blocks. It has been found shape, comprising the steps of filling a mold with that the upper part of the block can easily be kept molten steel, applying to the filled mold succesliquid and an approximately cylindrical shape is sively and in equal proportions a first layer of a given to it, if a covering substance is placed on heat generating composition, a second layer of the filled mold which covering consists of a first finely ground Martin slag and a third layer of layer of a heat generating substance such as a chamotte powder, allowing the mold to cool until 20 mixture of coal, coke and aluminium, a second its steel content has solidified over a predeterlayer of finely ground Martin slag (slag of a steel mined wall thickness, and then emptying the furnace) and a third layer of chamotte powder, mold. the layers being applied successively on the filled 2. A process for producing heavy hollow cast a mold in the quantitative ratio of 1:1:1. The steel blocks of substantially cylindrical internal use of heat radiating and heat insulating covershape, comprising the steps of filling a mold with ing substances is known in the ordinary steel molten steel, applying to the filled mold succesworks practice. These substances are, however, sively and in equal proportions a first layer 0t 80 intended to prevent the formation of pipes. a mixture of coal, coke and aluminium, a second Moreover, only two layers are used. However. layer of finely ground Martin slag and a third in the present instance the covering layers have a layer of chamotte powder, allowing the mold to diflerent purpose in view, namely to keep open cool untilits steel content has solidified over a the block head. Especially when the Martin slag predetermined wall thickness, and then emptying and chamotte' powder are added subsequently the' the mold. I eflect is obtained that the upper portion of the FRITZ HALBROCK. block remains liquid for a suiiiciently long time. WILHELM BAUMGARUI. 

